There are many applications where a socket is used to connect an integrated circuit (IC) device to a printed circuit board (PCB) so that the electrical connection is made in a separable manner. As illustrated in FIG. 1, a socket 20 in a test system 21 may receive a packaged integrated circuit 22 (IC package) and connect each terminal 24 on the IC package 22 to the corresponding terminal 26 on the PCB 28. The terminals 24 on the IC package 22 are held against contact members 32 by applying a load 30 that maintains intimate contact and reliable connection during testing. No permanent connection is required, such that the IC package 22 can be removed or replaced without the need for reflowing solder connections.
In general, sockets such as the socket 20 contain a series of contact members 32 that form the electrical interface between the IC package 22 and the PCB 28. At least one contact member 32 corresponds to each terminal 24. The contact members 32 have at least two interface points, a first interface 34 with a terminal 24 of the IC package 22 and a second interface 36 with a terminal 26 of the PCB 28. When a user utilizes the socket 20 to connect the IC package 22, the assumption is that the connection points at the first and second interfaces for each terminal 24 are reliable. In the event the system is powered and the function of the IC package 22 is not as expected, there are many connection points at the interfaces 34, 36 that may be the cause of the error. Trouble shooting or otherwise resolving these errors can be challenging.
If the IC package 22 is removed and replaced and the issue is resolved, then a conclusion can be drawn that all of the other components in the test system 21 are connected and functioning properly. In the event the error is not resolved or another issue is introduced, a user must systematically sort through the various components and connections within the test system 21 to resolve the issue. In many cases, the socket 20 may be a source of error due to the number of connections at the interfaces 34, 36 and the potential for at least one of those connections to be improperly positioned. The typical method is to replace the socket 20 with another socket, or place the socket 20 on an interface known to function properly to attempt to determine if the socket 20 is the source of the error. If the new socket functions properly, then the original socket 20 is deemed the problem. If the new socket does not work, then the issue is not resolved since the issue may be common or related to how the socket 20 interfaces to the IC package 22 or to the PCB 28. This systematic process can be extremely time consuming and can cause major delays, and can impact continued testing of IC packages.
There are several limitations to traditional methods of trouble shooting and resolving connection problems. The common method of replacing the socket 20 with another is typically the first avenue, and requires that additional sockets 20 are available. A successful result depends on whether the issue is isolated to the initial socket 20. This method can identify whether there is an anomaly with the initial socket 20 such as a damaged contact or poor connection. In the event the new socket does not produce desired results, further investigation is required. There may be a problem that is common to the sockets generally, and the user does not know if they need to look elsewhere or if the issue remains with the socket 20.
Another method may involve creating an external validation vehicle, such as a PCB that mimics the system board. This method can be more determinant than an “in the system” approach such as replacing the socket 20. The socket interfaces can be isolated and, if there is an issue with the group of contacts or specific contacts, the issue can be readily identified. One limitation with this method can be the requirement that these external tools be created ahead of time so they are available if and when they are needed. The result can be additional effort and expense that may not be needed if the socket 20 performs as expected.
Establishing these tools ahead of time can provide confidence that the socket is functioning properly and in the end reduce effort since the user can trust the socket is working. However, there is some risk that the external tools may not match the actual system circuit board precisely in form or function, and that issues that are not present on the external tools may be present on the system PCB. Another limitation with this method may be the adverse consequences of failing to produce these external tools ahead of time, since the lead time to design and produce these external tools can be long. Still another limitation is that an external circuit board or test system may not precisely match the make-up of the actual system and/or utilize an exact IC device. Typically, a surrogate IC device is used to simulate the actual IC device and a surrogate PCB is used to simulate the system PCB. The surrogate IC device and surrogate PCB may manifest issues different from or not present in the actual IC device and PCB. Similarly, the surrogates may not manifest issues present in the actual IC device and PCB. Accordingly, problems may go undetected.
In the event the foregoing methods do not identify the problem, the actual IC device may be soldered to the site intended for the socket to eliminate the socket from the equation. This method defeats the advantages of using a socket, including eliminating the desired separability.